1. Field
The disclosed apparatus and method relates to a facsimile apparatus, and more particularly to a facsimile apparatus that is capable of performing a plurality of standardized communications controls.
2. Discussion of the Related Art
There have been developed communications terminals such as facsimile apparatus that perform communications operations complied with communications protocols defined by recommendations V.8 and V.34 of the ITU-T (international telecommunication union-telecommunication standardization sector). The V.8 procedure defines procedures for starting sessions of data transmission over a PSTN (public switched telephone network) and that communications complying with the V.8 procedure are performed in a full duplex communications mode. The V.34 defines a modem operating at data signaling rates of up to 33,600 bps (bits per second) for use on the PSTN and on leased point-to-point 2-wire telephone-type networks.
The V.8 procedure defines various start-up signals to be transmitted between calling and called terminals over the PSTN. Examples of these signals include a CM (call menu) for calling a menu, a JM (joint menu) for jointing menus, and a CJ (call joint) for indicating a detection of the JM and a termination of the CM. Transmission of these signals is performed in either a full or half duplex transmission mode, depending upon transmission conditions.
Communications between terminals complying with the V.8 procedure in the full duplex transmission mode, typically requires a start-up procedure in which the calling and called terminals sequentially exchange the start-up signals. In addition, the called terminal sends an ANSam signal (answer amplitude-modulated) for designating the full duplex transmission mode and, after a certain period of time, the JM signal. Upon receiving the ANSam signal the calling terminal sends the CM signal and then receives the JM signal. After receiving the JM signal the calling terminal sends the CJ signal, and upon receiving the CM signal the called terminal sends the JM signal and then receives the CJ signal.
In general, communications between terminals each having a modem use a series of communications protocols called V series modem recommendations. The V series modem recommendations define the communications protocols with respect to the physical layer, and include the following protocols: V.17 for up to 14,400 bps; V.21 for data signaling rates of up to 300 bps; V.22 for up to 1,200 bps; V.22bis for up to 2,400 bps; V.29 for up to 9,600 bps; V.32 for up to 9,600; V.32bis for up to 14,400; and V.34 for up to 33,600 bps, for example. In particular, the V.17 and V.29 protocols have been used for the facsimile apparatus. Most modems that are presently in the market are designed in accordance with the above-mentioned V series modem recommendations. For example, communications between terminals each having a modem complying with the V.34 protocol can communicate at data signaling rates of 33,600 bps (optional), 31,200 bps (optional), 28,800 bps, 26,400 bps, 24,000 bps, 21,600 bps, 19,200 bps, 16,800 bps, 14,400 bps, 12,000 bps, 9,600 bps, 7,200 bps, 4,800 bps, and 2,400 bps. Before starting the data communications, the modems of the terminals automatically select the fastest rate from among data signaling rates applicable to the conditions of the telephone line at the time of performing the communications.
In facsimile apparatus that have a communications controller, such as a modem, for controlling communications in accordance with the V.8 and V.34 procedures, a transmission error during the V.8 start-up procedure may cause a relatively long waiting state and result in a communications failure that causes a line disconnection. More specifically, a transmission error may occur for any reason during the V.8 start-up procedure and a calling facsimile apparatus, for example, becomes unable to receive the JM signal after starting a timer T1 for measuring a time-out period. In this case, the calling facsimile apparatus inevitably continues to send the CM signal until a time-out period, typically preset to 35 seconds, is passed. After the time-out period of 35 seconds, a relatively long time to wait, the state is then regarded as a communications failure. FIG. 8 illustrates the communications procedure of this case, in which the start of the timer T1 is indicated by the arrow A and the time-out of the timer T1 is indicated by the arrow B.
Another example is illustrated in FIG. 9, in which a called facsimile apparatus becomes unable to receive the CJ following the CM by any reason after starting the timer T1 during the V.8 procedure. In this case, the called facsimile apparatus continues to send the JM until the time out period preset, to 35 seconds, is passed. After the time-out period of 35 seconds, a relatively long time to wait, the state is then regarded as a communications failure. In FIG. 9, the start of the timer T1 is indicated by the arrow A and the time-out of the timer T1 is indicated by the arrow B.
As described one problem with current V.8 communication procedures is that communication terminals are unable to avoid a communications failure resulting in a line disconnection when the preset time-out period T1 measured by the timer to occur during V.8 communications procedure. Another problem is that with current the V.8 communications procedure time is wasted by waiting for the time-out to occur.